This very thing was doing my absolute head in a few months ago - totally and utterly doing my head in. It made so little sense and I got so %^&*#^$# with it that I reverted to using old fashioned relays instead of the optocouplers.

Hi,
First of all. It's a software problem. I hope we could resolve this in the next beta, but it's a good practice to use 100KOhms pull-ups to economy power for battery supplied devices instead of internal pull-ups (about 10 KOhms).
I misunderstood what do you mean about "overload". It have to work with 4.7K normally. If you have some issues with it, please report.

I meant by "overload" that it is the electrical schematics that will have to have more resistance for each input. It's only that.
No electrical problem. And I confirm that with 4.7K external pull resistors all inputs work perfectly.
I'll wait for your update, just that will allow me not to redo all my drawings.and I can simply test with my schema at least 15 inputs, if you want.
Really thank you for your listening and impeccable follow-up, and really good job with this z-uno.

I have some problem with incude with eedomus box and i contact them for this issue.
The z-uno is detected instantly but the channels are poorly paired. and the number of channels that works is never the same.
I have test with 15 channels and it's very delicate for include the 15 channels.
We get there but it's very very long

Hi,
I found a another issue with the compiler and S2 security.
The burning of the bootloader is going very well, and when l load the program to the z-uno we have a mismatch error.
I did the test with compiler 1.6.5 and 1.8.5 and it's the same problem.
It works very well with version 2.1.3.

Hi, we work on the pullup issue. S2 issues was in the first beta. Could you check that you use "the last" beta and have this issue too? I couldn't reproduce it on my build.
Thank you! You really help us a lot!
Alex.

Hi,
Really with pleasure, this z-uno is great. And thank you for all these developments.
Great for pullup resistors, I hope it will not be too complicated.

For S2 issues, I just reproduced the problem with the latest beta (by remove all from packages/Z-Uno & staging/packages and reload board from test-ucxx repository). The compiler is 1.8.5.
I Restart Arduino IDE.
I change the card type, the frequency (europe), the security (S2) and the programmer.
I upgrade the bootloader first and ok.
I upload the sketch just after and error.

it does not matter to me because I'm not going to use security, but maybe it can happen to someone else